a) Field of the Invention
The present invention relates to an apparatus for treating a photosensitive material and a method of adding water into the same apparatus, in which the concentration of a treating solution accommodated within a treating tank of the apparatus is held constant.
b) Description of the Related Art
In an automatic developing machine, which forms part of the apparatus for treating the photosensitive material, a developing tank, bleaching tank, fixing tank, rinsing tank and a stabilizing tank are provided each respectively storing a developing solution, bleaching solution, fixing solution, rinsing solution and a stabilizing solution, (hereinafter generally referred to as a treating solution). The photosensitive material, which has been subjected to a printing procedure, is sequentially immersed into each of the treating tanks and, after being developed, it is introduced to a drying unit where it is dried prior to being withdrawn.
Since the treating solution is withdrawn by conveying the photosensitive material and is also decreased due to evaporation loss, it is necessary to replenish the loss as the throughput of the photosensitive material is increased. Incidentally, the amount of solution withdrawn by this photosensitive material can be readily calculated from the throughput of the photosensitive material. Meanwhile, as regards the above-described decrease of the treating solution due to evaporation loss, since the water content within the treating solution is decreased, the concentration of the treating solution is changed. Therefore, it is necessary to add an amount of water corresponding to the loss independently of the replenishing solution. However, the evaporation loss cannot be definably determined by calculation because it varies with the surrounding environment, such as temperature and humidity, and further depending on whether the apparatus is in an operating or shut down condition.
Accordingly, it is proposed to provide a level sensor, such as a gravimeter or the like, within each treating tank and add water based on a value, detected by this level sensor (see, for example, Japanese Patent Application Laid-Open No. 1-281446), according to which the changing concentration of the treating solution can be detected by the level sensor so that an appropriate amount of water can be added.
Nevertheless, the operating reliability of the level sensor is low and it often operates erroneously, often making the addition of an inappropriate amount of water possible. This is also true of the concentration sensor. In addition, these sensors are costly and lack serviceability. As a result, it is proposed to provide a monitoring treating tank that is independent of the actual treating tank and add water therein based on the evaporation loss of the latter (see Japanese Patent Application Laid-Open Nos. 1-254959 and 1-254960). Accordingly, operating reliability is increased because data approximating the actual evaporation loss can be obtained.
However, in the above-described water adding system, since the monitoring treating tank is independent of the actual treating tank, the entire apparatus becomes bulky and the number of parts required increase. In addition, in order to set similar conditions as in the actual treating tank, management and maintenance become complicated.